On the Spin of the X(3872)

Whether the much studied X(3872) is an axial or tensor resonance makes an important difference to its interpretation. A recent paper by the BaBar collaboration raised the viable hypothesis that it might be a 2-+ state based on the 3 pions spectrum in the X -> J/psi omega decays. Furthermore, the Belle collaboration published the 2 pions invariant mass and spin-sensitive angular distributions in X -> J/psi rho decays. Starting from a general parametrization of the decay amplitudes for the axial and tensor quantum numbers of the X, we re-analyze the whole set of available data. The level of agreement of the two spin hypotheses with data is interpreted with a rigorous statistical approach based on Monte Carlo simulations in order to be able to combine all the distributions regardless of their different levels of sensitivity to the spin of the X. Our analysis returns a probability of 5.5% and 0.1% for the agreement with data of the 1++ and 2-+ hypotheses, respectively, once we combine the whole information (angular and mass distributions) from both channels. On the other hand, the separate analysis of J/psi rho (angular and mass distributions) and J/psi omega (mass distribution) indicates that the 2-+ assignment is excluded at the 99.9% C.L. by the former case, while the latter excludes at the same level the 1++ hypothesis. There are therefore indications that the two decay modes behave in a different way.Comment: 12 pages, 9 figures, 2 tables. Added angular distributions, which lead to different conclusion

Fault Tolerance Analysis of a Bis-Ferrocene QCA Wire

Molecular Quantum Dot Cellular Automata (mQCA) are among the most promising emerging technologies for the expected theoretical operating frequencies (THz), the high device densities and the non-cryogenic working temperature. In this paper, we performed an analysis of the possible fabrication defects of a molecular QCA wire built with ad-hoc synthesized bis-ferrocene molecules. We then evaluated the fault tolerance of a real QCA device and assessed its performance in non-ideal conditions, by defining a new methodology for the fault analysis in the mQCA technolog

Pattern characterization of genes involved in non-specific immune response in Staphylococcus aureus isolates from intramammary infections

Staphylococcus aureus isolated from mammary gland are characterized by different genetic patterns. Ninety four isolates from 33 dairy herds were analyzed by the means of amicroarray to investigate S. aureus virulence patterns and the distribution of genes believed to be involved in immune evasion. None of the 94 isolates considered were MRSA. However, 50% of the isolates belonged to complexes related to MRSA and to human diseases, while only about 25% of them can be considered as exclusively of bovine origin. The distribution of clonal complexes and the different gene patterns observed confirmed the presence of an influence of geographical localization. The assessment of the influence of genes related to immune evasion on quarter milk cell count showed as four of them showed to be significantly associated to an increase quarter milk SCC. These genes could be potential target for developing new vaccines against S.aureus

Effects of an inactivated vaccine for bovine mycoplasmosis on calves naturally affected with Mycoplasma bovis

Three autogenous vaccine trials were carried out on farms where Mycoplasma bovis had been identified as a major pathogen. The first trial was carried on a veal farm in the Lombardia region of northern Italy. Vaccine, prepared by saponising an M bovis strain taken from the farm some months before, was given as single inoculation to 24 calves on arrival while 19 were left unvaccinated. Six months later calves were sent to the abattoir where lungs were examined for gross pathological lesions. The mean weight of the vaccinated group was higher though not significantly so and mean lesion scores were similar; however the percentage of vaccinated calves with severe lung lesions and pleuritis was lower than in the non vaccinates. A second trial was carried out in northern England on a farm where monthly batches of male calves from a nearby dairy herd were reared under a feedlot system. One group of 27 calves were vaccinated with a saponised strain of M bovis isolated from the lungs of a pneumonic calf on the farm prior to the start of the trial. A second batch of 25 calves was left unvaccinated. The groups of calves were monitored for nine months prior to slaughter and records kept of antibiotic usage and mortality. The mortality rates in the vaccinated calves were about 15% compared to 28% in unvaccinated calves; however there was no difference in the number of times calves were treated for respiratory disease. A third batch of calves, treated with oxytetracycline on arrival because a number were already showing respiratory signs, had a lower mortality rate and fewer subsequent treatments. A third trial was carried out on a milk veal unit in the Veneto region of Italy. A group of 19 calves were vaccinated on arrival with a saponised isolate taken earlier from the farm; a similar number of calves of the same batch were left unvaccinated. After 6 months animals were routinely processed at the abattoir and lungs inspected. Results showed that vaccinated calves had higher mean body weights and although similar mean lung scores there was a smaller percentage of vaccinated calves with severe lung lesions and pleuritis

Time-Domain Analysis of Chalcogenide Threshold Switching: From ns to ps Scale

A space- and time-dependent theoretical model based on a trap-assisted, charge-transport framework for the amorphous phase of a chalcogenide material is used here to interpret available experimental results for the electric current of nanoscale devices in the ns–ps time domain. A numerical solution of the constitutive equations of the model for a time-dependent bias has been carried out for GST-225 devices. The “intrinsic” rise time of the device current after the application of a suitable external bias is controlled by the microscopic relaxation of the mobile-carrier population to the steady-state value. Furthermore, the analysis is extended to include the effect of the external circuit on the electrical switching. A quantitative estimate of the current delay time due to unavoidable parasitic effects is made for the optimised electrical set up configurations recently used by experimental groups

Strong Couplings of X(3872)_{J=1,2} and a New Look at J/psi Suppression in Heavy Ion Collisions

We define and compute from data the strong couplings of the X(3872) with both of the possible quantum numbers assignments J^{PC}=1^{++},2^{-+}. We use these to compute cross sections for J/psi resonance scattering into D Dbar*. As an application of the results obtained we revise the calculation of the J/psi absorption in a hot hadron gas to confront with recent RHIC observations in Au-Au collisions.Comment: 23 pages, 18 figures, 4 table

Fully-digital low-frequency lock-in amplifier for photoluminescence measurements

Lock-in amplifiers, used in several experimental physics applications, are instruments performing quadrature demodulation, which is useful when signals are affected by much noise. Generally, commercially-available lock-in amplifiers are very accurate, but expensive, especially if their operating range includes radiofrequencies. In many applications, high precision is not necessary for the measurements, but it is preferable to have low-cost, low-weight, compactness and a user-friendly graphical unit interface. In this paper, we describe a new fully-digital low-frequency lock-in amplifier developed at ENEA C.R. Frascati Laboratories for photoluminescence experiments based on an innovative low-cost architecture and processing algorithms. The hardware, firmware and software developed for the whole photoluminescence measurement set-up is presented. The present lock-in was first characterized with synthetic electrical sine wave signals and white noise. A dynamic reserve of 43 dB and a noise figure in the range of 25–44 dB were estimated. These results show compatibility with several measurement applications, such as photoluminescence, and the adequacy of the resolutions with respect to the hardware costs. Finally, preliminary results of photoluminescence measurements are presented

A complete one-loop calculation of electroweak supersymmetric effects in tt-channel single top production at LHC

We have computed the complete one-loop electroweak effects in the MSSM for single top (and single antitop) production in the $t$-channel at hadron colliders, generalizing a previous analysis performed for the dominant $dt$ final state and fully including QED effects. The results are quite similar for all processes. The overall Standard Model one-loop effect is small, of the few percent size. This is due to a compensation of weak and QED contributions that are of opposite sign. The genuine SUSY contribution is generally quite modest in the mSUGRA scenario. The experimental observables would therefore only practically depend, in this framework, on the CKM $Wtb$ coupling.Comment: 25 pages, several eps figures. Update corresponding to published versio